Tiotropium bromide (Ba 679 BR), a novel long-acting muscarinic antagonist for the treatment of obstructive airways disease

Structure-affinity and structure-residence time relationships of macrocyclic Gαq protein inhibitors

The macrocyclic depsipeptides YM-254890 (YM) and FR900359 (FR) are potent inhibitors of Gα_q/11 proteins. They are important pharmacological tools and have potential as therapeutic drugs. The hydrogenated, tritium-labeled YM and FR derivatives display largely different residence times despite similar structures. In the present study we established a competition-association binding assay to determine the dissociation kinetics of unlabeled G_q protein inhibitors. Structure-affinity and structure-residence time relationships were analyzed. Small structural modifications had a large impact on residence time. YM and FR exhibited 4- to 10-fold higher residence times than their hydrogenated derivatives. While FR showed pseudo-irreversible binding, YM displayed much faster dissociation from its target. The isopropyl anchor present in FR and some derivatives was essential for slow dissociation. These data provide a basis for future drug design toward modulating residence times of macrocyclic G_q protein inhibitors, which has been recognized as a crucial determinant for therapeutic outcome.

Efficacy and safety of tiotropium bromide inhalation in symptomatic patients with chronic obstructive pulmonary disease: A multicenter, prospective, and observational study

OBJECTIVES

Treatment guidelines have recommended tiotropium bromide inhalation (TBI), a long-acting muscarinic antagonist, for chronic obstructive pulmonary disease (COPD); however, its efficacy in symptomatic Chinese patients with COPD remains uninvestigated.

METHODS

This multicenter, prospective, observational study enrolled patients with COPD assessment test (CAT) scores exceeding 10 points from 19 hospitals spread across China. All patients received TBI and underwent follow-up for 3 months. The demographic and clinical information were assessed.

RESULTS

The final analysis included 378 patients. The forced expiratory volume in 1 s (FEV₁) and FEV₁/forced vital capacity (FVC) of all participants improved markedly after 3 months of treatment (FEV₁: mean 1.33 L versus 1.61 L, P < 0.001; FEV₁/FVC: mean 0.53 versus 0.62, P < 0.001). The mean CAT scores decreased from 26.56 to 16.28 (P < 0.001). Patients classified into group D based on the Global Initiative for COPD guidelines showed greater improvement in FEV₁ and FEV₁/FVC than that in patients in group B. The proportion of patients with acute exacerbations also declined from 28.6% in the first month to 4.2% in the third month.

CONCLUSION

TBI for 3 months could effectively and safely attenuate symptoms and airflow obstruction in symptomatic Chinese patients with COPD.

Muscarinic receptor M3 activation promotes fibrocytes contraction

Fibrocytes are monocyte-derived cells able to differentiate into myofibroblasts-like cells. We have previously shown that they are increased in the bronchi of Chronic Obstructive Pulmonary Disease (COPD) patients and associated to worse lung function. COPD is characterized by irreversible airflow obstruction, partly due to an increased cholinergic environment. Our goal was to investigate muscarinic signalling in COPD fibrocytes. Fibrocytes were isolated from 16 patients with COPD’s blood and presence of muscarinic M3 receptor was assessed at the transcriptional and protein levels. Calcium signalling and collagen gels contraction experiments were performed in presence of carbachol (cholinergic agonist) ± tiotropium bromide (antimuscarinic). Expression of M3 receptor was confirmed by Western blot and flow cytometry in differentiated fibrocytes. Immunocytochemistry showed the presence of cytoplasmic and membrane-associated pools of M3. Stimulation with carbachol elicited an intracellular calcium response in 35.7% of fibrocytes. This response was significantly blunted by the presence of tiotropium bromide: 14.6% of responding cells (p < 0.0001). Carbachol induced a significant contraction of fibrocytes embedded in collagen gels (13.6 ± 0.3% versus 2.5 ± 4.1%; p < 0.0001), which was prevented by prior tiotropium bromide addition (4.1 ± 2.7% of gel contraction; p < 0.0001). Finally, M3-expressing fibrocytes were also identified in situ in the peri-bronchial area of COPD patients’ lungs, and there was a tendency to an increased density compared to healthy patient’s lungs. In conclusion, around 1/3 of COPD patients’ fibrocytes express a functional muscarinic M3 receptor. Cholinergic-induced fibrocyte contraction might participate in airway diameter reduction and subsequent increase of airflow resistance in patients with COPD. The inhibition of these processes could participate to the beneficial effects of muscarinic antagonists for COPD treatment.

Cost-Effectiveness of Tiotropium in Elderly Patients with Severe Asthma Using Real-World Data

BACKGROUND

Tiotropium has the potential to alleviate asthmatic symptoms caused by the aging of lungs. However, few studies have focused on specific treatments for elderly patients with asthma.

OBJECTIVES

To estimate the cost-effectiveness of adding tiotropium to inhaled corticosteroids and long-acting beta-agonists in elderly patients with severe asthma using real-world data.

METHODS

Phase I was a retrospective cohort study using the National Health Insurance claims data to measure clinical and economic outcomes. In phase II, a Markov model was constructed to evaluate cost-effectiveness from Korean health care system perspective, based on phase I, including 2 health states, and an asthma exacerbation event. We estimated cost given in 2018 US dollars, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio. Subgroup analyses for patients with poorly controlled symptoms (frequent short-acting beta-agonist users; frequent exacerbators) were performed.

RESULTS

In elderly patients with severe asthma, the incremental cost and effectiveness in the tiotropium group compared with the inhaled corticosteroid and long-acting beta-agonist group were $2281 and 0.038 QALYs, respectively. The incremental cost-effectiveness ratio was $60,074/QALY, indicating that the addition of tiotropium is not a cost-effective alternative. Meanwhile, 2 subgroups with poorly controlled symptoms showed that adding tiotropium is a cost-effective alternative (frequent short-acting beta-agonist users $4078/QALY; frequent exacerbators $8332/QALY).

CONCLUSIONS

Tiotropium shows a higher cost-effectiveness profile when applied to elderly patients with uncontrolled symptoms. These results using real-world evidence provide information beyond the clinical outcomes reported by randomized controlled trials, providing a complementary ground in establishing the reimbursement criteria of tiotropium for elderly patients with severe asthma.

Inhaled Janus Kinase (JAK) inhibitors for the treatment of asthma

Multiple asthma-relevant cytokines including IL-4, IL-5, IL-13, and TSLP depend upon JAKs for signaling. JAK inhibition may, therefore, offer a novel intervention strategy for patients with disease refractory to current standards of care. Multiple systemically delivered JAK inhibitors have been approved for human use or are under clinical evaluation in autoimmune diseases such as rheumatoid arthritis. However, the on-target side effect profiles of these agents are likely not tolerable for many asthmatic patients. Limiting JAK inhibition to the lung is expected to improve therapeutic index relative to systemic inhibition. Thus, inhaled JAK inhibitors with lung-restricted exposure are of high interest as potential treatments for asthma.

Pharmacological Profile of AZD8871 (LAS191351), a Novel Inhaled Dual M3 Receptor Antagonist/β 2-Adrenoceptor Agonist Molecule with Long-Lasting Effects and Favorable Safety Profile

AZD8871 is a novel muscarinic antagonist and β ₂-adrenoceptor agonist in development for chronic obstructive pulmonary disease. This study describes the pharmacological profile of AZD8871 in in vitro and in vivo assays. AZD8871 is potent at the human M₃ receptor (pIC₅₀ in binding assays: 9.5) and shows kinetic selectivity for the M₃ (half-life: 4.97 hours) over the M₂ receptor (half-life: 0.46 hour). It is selective for the β ₂-adrenoceptor over the β ₁ and β ₃ subtypes (3- and 6-fold, respectively) and shows dual antimuscarinic and β ₂-adrenoceptor functional activity in isolated guinea pig tissue (pIC₅₀ in electrically stimulated trachea: 8.6; pEC₅₀ in spontaneous tone isolated trachea: 8.8, respectively), which are sustained over time. AZD8871 exhibits a higher muscarinic component than batefenterol in human bronchi, with a shift in potency under propranolol blockade of 2- and 6-fold, respectively, together with a persisting relaxation (5.3% recovery at 8 hours). Nebulized AZD8871 prevents acetylcholine-induced bronchoconstriction in both guinea pig and dog with minimal effects on salivation and heart rate at doses with bronchoprotective activity. Moreover, AZD8871 shows long-lasting effects in dog, with a bronchoprotective half-life longer than 24 hours. In conclusion, these studies demonstrate that AZD8871 is a dual-acting molecule with a high muscarinic component and a long residence time at the M₃ receptor; moreover, its preclinical profile in animal models suggests a once-daily dosing in humans and a favorable safety profile. Thus, AZD8871 has the potential to be a next generation of inhaled bronchodilators in respiratory diseases.

Nebulized Terbutaline and Ipratropium Bromide Versus Terbutaline Alone in Acute Exacerbation of Chronic Obstructive Pulmonary Disease Requiring Noninvasive Ventilation: A Randomized Double-blind Controlled Trial

BACKGROUND

Short-acting β₂ -agonists are the mainstay of treatment of patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in the emergency department (ED). It is still unclear whether the addition of short-acting anticholinergics is clinically more effective care compared to treatment with β₂ -agonists alone in patients with hypercapnic AECOPD.

OBJECTIVE

The objective was to evaluate whether combining ipratropium bromide (IB) to terbutaline reduces hospital and intensive care unit (ICU) admission rates compared to terbutaline alone in AECOPD hypercapnic patients.

METHODS

In this double-blind controlled trial, patients who were admitted to the ED for AECOPD requiring noninvasive ventilation (NIV) were randomized to receive either 5 mg of nebulized terbutaline combined to 0.5 mg of IB (terbutaline/IB group, n = 115) or 5 mg of terbutaline sulfate (terbutaline group, n = 117). Nebulization was repeated every 20 minutes for the first hour and every 4 hours within the first day. Primary outcomes were the rate of hospital admission and need for endotracheal intubation within the first 24 hours of the start of the experimental treatment. Secondary outcomes included changes from baseline of dyspnea, physiologic variables, length of hospital stay, ICU admission rate, and 7-day mortality.

RESULTS

The two groups were similar regarding baseline demographic and clinical characteristics. Hospital admission was observed in 70 patients (59.8%) in the terbutaline/IB group and in 75 patients (65.2%) in the terbutaline group (respiratory rate [RR] = 1.09, 95% confidence interval [CI] = 0.93 to 1.27, p = 0.39). ICU admission was required in 37 (32.2%) patients in the terbutaline/IB group and 30 patients (25.6%) in terbutaline group (RR = 1.25, 95% CI = 1.02 to 1.54, p = 0.27). There were no significant differences in dyspnea score, blood gas parameters changes, vital signs improvement, and 7-day death rate between both groups.

CONCLUSION

In patients admitted to the ED for AECOPD requiring NIV, combination of nebulized IB and terbutaline did not reduce hospital admission and need to ICU care.

The evidence on tiotropium bromide in asthma: from the rationale to the bedside

Severe and poorly controlled asthma still accounts for a great portion of the patients affected. Disease control and future risk management have been identified by international guidelines as the main goals in patients with asthma. The need for new treatment approaches has led to reconsider anticholinergic drugs as an option for asthma treatment. Tiotropium is the first anticholinergic drug that has been approved for children and adults with poorly controlled asthma and is currently considered as an option for steps 4 and 5 of the Global Initiative for Asthma. In large randomized clinical trials enrolling patients with moderate to severe asthma, add-on therapy with tiotropium has demonstrated to be efficacious in improving lung function, decreasing risk of exacerbation and slowing the worsening of disease; accordingly, tiotropium demonstrated to be non inferior compared to long acting beta-agonists in the maintenance treatment along with medium to high inhaled corticosteroids. In view of the numerous ancillary effects acting on inflammation, airway remodeling, mucus production and cough reflex, along with the good safety profile and the broad spectrum of efficacy demonstrated in different disease phenotypes, tiotropium can represent a beneficial alternative in the therapeutic management of poorly controlled asthma. The present extensive narrative review presents the pharmacological and pathophysiological basis that guided the rationale for the introduction of tiotropium in asthma treatment algorithm, with a particular focus on its conventional and unconventional effects; finally, data on tiotropium efficacy and safety. from recent randomized clinical trials performed in all age categories will be extensively discussed.

Acetylcholine polarizes dendritic cells toward a Th2-promoting profile

BACKGROUND

A growing body of research shows a reciprocal regulation between the neural and immune systems. Acetylcholine (ACh) is the most important parasympathetic neurotransmitter, and increasing evidence indicates that it is able to modulate the immune response. Interestingly, in recent years, it has become clear that immune cells express a non-neuronal cholinergic system, which is stimulated in the course of inflammatory processes. We have previously shown that dendritic cells (DC) express muscarinic receptors, as well as the enzymes responsible for the synthesis and degradation of ACh. Here, we analyzed whether ACh could also modulate the functional profile of DC.

METHODS

Dendritic cells were obtained from monocytes cultured for 5 days with GM-CSF+IL-4 or isolated from peripheral blood (CD1c+ DC). The phenotype of DC was evaluated by flow cytometry, the production of cytokines was analyzed by ELISA or intracellular staining and flow cytometry, and the expression of muscarinic and nicotinic receptors was evaluated by flow cytometry or qRT-PCR.

RESULTS

Treatment of DC with ACh stimulated the expression of the Th2-promoter OX40L, the production of the Th2-chemokines MDC (macrophage-derived chemokine/CCL22) and TARC (thymus and activation-regulated chemokine/CCL17), and the synthesis of IL-4, IL-5, and IL-13 by T cells, in the course of the mixed lymphocyte reaction (MLR). Moreover, we found that the stimulation of OX40L, HLA-DR, and CD83 expressions in DC induced by the Th2-promoting cytokine TSLP, as well as the production of IL-13, IL-4, and IL-5 by T cells in the course of the MLR, was further enhanced when DC were treated with TSLP plus ACh, instead of TSLP or ACh alone.

CONCLUSIONS

Our observations suggest that ACh polarizes DC toward a Th2-promoting profile.

Clinical efficacy of tiotropium in children with asthma

OBJECTIVE

To investigate the clinical efficacy of tiotropium in children with asthma.

METHODS

Eighty children with newly diagnosed moderate persistent asthma were enrolled into this study. The children were randomly assigned to the fluticasone propionate aerosol group or the fluticasone propionate aerosol plus tiotropium group for 12 weeks.

RESULTS

Lung function was significantly improved in both groups at 4, 8, and 12 weeks compared with baseline (P < 0.01). Moreover, lung function was significantly improved in the tiotropium group compared with the control group (P < 0.05). However, there was no significant difference in the incidence of severe asthma between the two groups (36.3% and 26.8%, respectively; P > 0.05). Compared with the control group, the number of days and frequency of short-acting beta2-adrenoceptor agonist use was significantly reduced in the tiotropium group (P < 0.05). Awakenings during the night were also significantly decreased (P < 0.00). There were no severe adverse reactions in either of the study groups.

CONCLUSION

Tiotropium could significantly improve lung function, reduce the use of short-acting beta2-adrenoceptor agonists, and improve sleep in children with asthma. Furthermore, few adverse reactions were reported.

Pharmacotherapy in the management of asthma in the elderly: a review of clinical studies

Asthma in the elderly is a disease with emerging concern. Despite some recent advances in our understanding of epidemiology and pathophysiology, there is a considerable lack of clinical evidence specific to elderly patients. Currently available high quality clinical evidence has been mostly obtained from younger adults, but rarely from elderly patients. Under-representation of elderly patients in previous randomized trials may have been due to being, old age, or having comorbidities. Thus, a question may be raised whether current clinical evidence could be well generalized into elderly patients. Further clinical trials should address clinical issues raised in elderly population. In this review, we aimed to overview the efficacy and safety of pharmacological management, and also to summarize the literature relevant to elderly asthma.

Pharmacologic characterization of GSK-961081 (TD-5959), a first-in-class inhaled bifunctional bronchodilator possessing muscarinic receptor antagonist and β2-adrenoceptor agonist properties

The objective of the present studies was to characterize the pharmacologic properties of GSK-961081 [TD-5959; (R)-1-(3-((2-chloro-4-(((2-hydroxy-2-(8-hydroxy-2-oxo-1,2-dihydroquinolin-5-yl)ethyl)amino)methyl)-5-methoxyphenyl)amino)-3-oxopropyl) piperidin-4-yl [1,1'-biphenyl]-2-ylcarbamate], a novel first-in-class inhaled bifunctional compound possessing both muscarinic antagonist (MA) and β2-adrenoceptor agonist (BA) properties (MABA). In competition radioligand binding studies at human recombinant receptors, GSK-961081 displayed high affinity for hM2 (Ki = 1.4 nM), hM3 muscarinic receptors (Ki = 1.3 nM) and hβ2-adrenoceptors (Ki = 3.7 nM). GSK-961081 behaved as a potent hβ2-adrenoceptor agonist (EC50 = 0.29 nM for stimulation of cAMP levels) with 440- and 320-fold functional selectivity over hβ1- and hβ3-adrenoceptors, respectively. In guinea pig isolated tracheal tissues, GSK-961081 produced smooth muscle relaxation through MA (EC50 = 50.2 nM), BA (EC50=24.6 nM), and MABA (EC50 = 11 nM) mechanisms. In the guinea pig bronchoprotection assay, inhaled GSK-961081 produced potent, dose-dependent inhibition of bronchoconstrictor responses via MA (ED50 = 33.9 µg/ml), BA (ED50 = 14.1 µg/ml), and MABA (ED50 = 6.4 µg/ml) mechanisms. Significant bronchoprotective effects of GSK-961081 were evident in guinea pigs via MA, BA, and MABA mechanisms for up to 7 days after dosing. The lung selectivity index of GSK-961081 in guinea pigs was 55- to 110-fold greater than that of tiotropium with respect to systemic antimuscarinic antisialagogue effects and was 10-fold greater than that of salmeterol with respect to systemic β2-adrenoceptor hypotensive effects. These preclinical findings studies suggest that GSK-961081 has the potential to be a promising next-generation inhaled lung-selective bronchodilator for the treatment of airway diseases, including chronic obstructive pulmonary disease.

Tiotropium modulates transient receptor potential V1 (TRPV1) in airway sensory nerves: A beneficial off-target effect?

Background

Recent studies have suggested that the long-acting muscarinic receptor antagonist tiotropium, a drug widely prescribed for its bronchodilator activity in patients with chronic obstructive pulmonary disease and asthma, improves symptoms and attenuates cough in preclinical and clinical tussive agent challenge studies. The mechanism by which tiotropium modifies tussive responses is not clear, but an inhibition of vagal tone and a consequent reduction in mucus production from submucosal glands and bronchodilation have been proposed.

Objective

The aim of this study was to investigate whether tiotropium can directly modulate airway sensory nerve activity and thereby the cough reflex.

Methods

We used a conscious cough model in guinea pigs, isolated vagal sensory nerve and isolated airway neuron tissue– and cell-based assays, and in vivo single-fiber recording electrophysiologic techniques.

Results

Inhaled tiotropium blocked cough and single C-fiber firing in the guinea pig to the transient receptor potential (TRP) V1 agonist capsaicin, a clinically relevant tussive stimulant. Tiotropium and ipratropium, a structurally similar muscarinic antagonist, inhibited capsaicin responses in isolated guinea pig vagal tissue, but glycopyrrolate and atropine did not. Tiotropium failed to modulate other TRP channel–mediated responses. Complementary data were generated in airway-specific primary ganglion neurons, demonstrating that tiotropium inhibited capsaicin-induced, but not TRPA1-induced, calcium movement and voltage changes.

Conclusion

For the first time, we have shown that tiotropium inhibits neuronal TRPV1-mediated effects through a mechanism unrelated to its anticholinergic activity. We speculate that some of the clinical benefit associated with taking tiotropium (eg, in symptom control) could be explained through this proposed mechanism of action.

Experimental models to study drug distributions in tissue using MALDI mass spectrometry imaging

Requirements for patient safety and improved efficacy are steadily increasing in modern healthcare and are key drivers in modern drug development. New drug characterization assays are central in providing evidence of the specificity and selectivity of drugs. Meeting this need, matrix-assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) is used to study drug localization within microenvironmental tissue compartments. Thin sections of human lung tumor and rat xenograft tissues were exposed to pharmaceutical drugs by either spotting or submerging. These drugs, the epidermal growth factor receptor antagonists, erlotinib (Tarceva) and gefitinib (Iressa), and the acetylcholine receptor antagonist, tiotropium, were characterized by microenvironment localization. Intact tissue blocks were also immersed in drug solution, followed by sectioning. MALDI-MSI was then performed using a Thermo MALDI LTQ Orbitrap XL instrument to localize drug-distribution patterns. We propose three MALDI-MSI models measuring drug disposition that have been used to map the selected compounds within tissue compartments of tumors isolated from lung cancer patients.

Effects of tiotropium on lung function in severe asthmatics with or without emphysematous changes

The effects of tiotropium, an inhaled long-acting anti-cholinergic agent, on lung function were investigated in obstructed severe asthmatics with and without emphysematous changes despite maximal recommended treatments with high-dose of inhaled glucocorticoids and inhaled long-acting β(2)-agonists. We conducted a double-blind, placebo-controlled study of an inhaled single-dose of tiotropium in 18 asthmatics with emphysema and 18 without emphysema in a crossover manner. The primary efficacy outcome was the relative change in forced expiratory volume in 1 s (FEV(1)) from baseline to 60 min, and the secondary outcome was a relative change in FEV(1) from baseline to 12 h. Subsequently, the patients were treated with tiotropium inhaled once daily for 12 weeks in an open label manner, and lung function and symptoms were evaluated. At baseline, patients with or without emphysema had a mean FEV(1) of 55.9% before tiotropium and 56.8% before placebo, or 77.4% before tiotropium and 77.6% before placebo of the predicted value and were taking a mean dose of inhaled glucocorticoids of 1444 or 1422 μg/day. Among patients with emphysema, the increase from baseline FEV(1) was 12.6 percentage points higher at 60 min after tiotropium than after placebo. Among patients without emphysema, the increase from baseline FEV(1) was 5.4 percentage points higher at 60 min after tiotropium than after placebo. Tiotropium resulted in improved lung function and symptoms in asthmatics with and without emphysema. These findings suggest that tiotropium will provide a new strategy for the treatment of bronchial asthma and of overlapping asthma and COPD.

Airway responsiveness to psychological processes in asthma and health

Psychosocial factors have been found to impact airway pathophysiology in respiratory disease with considerable consistency. Influences on airway mechanics have been studied particularly well. The goal of this article is to review the literature on airway responses to psychological stimulation, discuss potential pathways of influence, and present a well-established emotion-induction paradigm to study airway obstruction elicited by unpleasant stimuli. Observational studies have found systematic associations between lung function and daily mood changes. The laboratory-based paradigm of bronchoconstrictive suggestion has been used successfully to elicit airway obstruction in a substantial proportion of asthmatic individuals. Other studies have demonstrated modulation of airway responses to standard airway challenges with exercise, allergens, or pharmacological agents by psychological factors. Standardized emotion-induction techniques have consistently shown airway constriction during unpleasant stimulation, with surgery, blood, and injury stimuli being particularly powerful. Findings with various forms of stress induction have been more mixed. A number of methodological factors may account for variability across studies, such as choice of measurement technique, temporal association between stimulation and measurement, and the specific quality and intensity of the stimulus material, in particular the extent of implied action-orientation. Research has also begun to elucidate physiological processes associated with psychologically induced airway responses, with vagal excitation and ventilatory influences being the most likely candidate pathways, whereas the role of specific central nervous system pathways and inflammatory processes has been less studied. The technique of emotion-induction using films has the potential to become a standardized challenge paradigm for the further exploration of airway hyperresponsiveness mediated by central nervous system processes.

Measuring receptor target coverage: a radioligand competition binding protocol for assessing the association and dissociation rates of unlabeled compounds

The kinetics of the ligand-receptor interaction is an important feature in lead optimization for new drug candidates. The protocol described in this unit is a kinetic radioligand competition binding assay that makes possible the determination of both the association and dissociation rates of unlabeled receptor ligands.

Regulation of airway inflammation and remodeling by muscarinic receptors: perspectives on anticholinergic therapy in asthma and COPD

Acetylcholine is the primary parasympathetic neurotransmitter in the airways and an autocrine/paracrine secreted hormone from non-neuronal origins including inflammatory cells and airway structural cells. In addition to the well-known functions of acetylcholine in regulating bronchoconstriction and mucus secretion, it is increasingly evident that acetylcholine regulates inflammatory cell chemotaxis and activation, and also participates in signaling events leading to chronic airway wall remodeling that is associated with chronic obstructive airway diseases including asthma and COPD. As muscarinic receptors appear responsible for most of the pro-inflammatory and remodeling effects of acetylcholine, these findings have significant implications for anticholinergic therapy in asthma and COPD, which is selective for muscarinic receptors. Here, the regulatory role of acetylcholine in inflammation and remodeling in asthma and COPD will be discussed including the perspectives that these findings offer for anticholinergic therapy in these diseases.

Differential expression of the β2-adrenoreceptor and M3-cholinoreceptor genes in bronchial mucosa of patients with asthma and chronic obstructive pulmonary disease

BACKGROUND

Bronchodilators are drugs of choice in the combined therapy of bronchial asthma and chronic obstructive pulmonary disease (COPD). However, the therapeutic sensitivity is variable between patients, probably because of structural features of regulating molecules or variation in key genes' expression.

OBJECTIVES

The aim of this study was to evaluate the β2-adrenoceptor (ADRB2) and M3-cholinoreceptor (CHRM3) gene expression in bronchial mucosa in patients with COPD and different severity of asthma.

METHODS

Biopsy specimens of right middle lobar bronchus were obtained from 59 asthma patients (10 patients with severe brittle phenotype, 14 patients with severe asthma with persistent airflow limitation, 27 patients with moderate asthma, and 8 patients with mild asthma) and 10 COPD patients with or without bronchial hyperresponsiveness (BHR). The messenger RNA (mRNA) levels for the ADRB2 and CHRM3 genes in bronchial mucosa were revealed using quantitative reverse transcription polymerase chain reaction (RT-PCR) and compared between groups.

RESULTS

An increase of the ADRB2 genes expression was demonstrated in patients with severe asthma and COPD as compared with patients with mild and moderate disease. Significantly higher levels of ADRB2 mRNA were observed in patients with severe asthma with persistent airflow limitation. Significantly lower levels of the CHRM3 mRNA were observed in patients with COPD as compared with asthma patients. Also, CHRM3 gene expression was significantly elevated in COPD patients with BHR as compared with patients without BHR.

CONCLUSIONS

The results of the study suggest that the differential expression of the ADRB2 and CHRM3 genes is associated with asthma and COPD clinical subtypes.

Muscarinic receptor antagonists, from folklore to pharmacology; finding drugs that actually work in asthma and COPD

In the lungs, parasympathetic nerves provide the dominant control of airway smooth muscle with release of acetylcholine onto M3 muscarinic receptors. Treatment of airway disease with anticholinergic drugs that block muscarinic receptors began over 2000 years ago. Pharmacologic data all indicated that antimuscarinic drugs should be highly effective in asthma but clinical results were mixed. Thus, with the discovery of effective β-adrenergic receptor agonists the use of muscarinic antagonists declined. Lack of effectiveness of muscarinic antagonists is due to a variety of factors including unwanted side effects (ranging from dry mouth to coma) and the discovery of additional muscarinic receptor subtypes in the lungs with sometimes competing effects. Perhaps the most important problem is ineffective dosing due to poorly understood differences between routes of administration and no effective way of testing whether antagonists block receptors stimulated physiologically by acetylcholine. Newer muscarinic receptor antagonists are being developed that address the problems of side effects and receptor selectivity that appear to be quite promising in the treatment of asthma and chronic obstructive pulmonary disease.

Indacaterol provides 24-hour bronchodilation in COPD: a placebo-controlled blinded comparison with tiotropium

BACKGROUND

Indacaterol is a novel, inhaled, once-daily, ultra-long-acting β2-agonist for the treatment of chronic obstructive pulmonary disease (COPD). This randomized, double-blind study compared the bronchodilator efficacy of indacaterol with that of placebo and tiotropium in patients with moderate-to-severe COPD.

METHODS

In an incomplete-block, multi-dose, three-period, crossover design, patients received three of the following four treatments: indacaterol 150 μg, indacaterol 300 μg, tiotropium 18 μg and placebo, each once-daily for 14 days. Each treatment period was separated by a 14-day washout. Study drug was supplied daily by blinded, third party study personnel to maintain blinding of patients and investigators. The primary efficacy variable was trough forced expiratory volume in one second (FEV1) at 24 h post-dose after 14 days. The study was powered to demonstrate non-inferiority of indacaterol to tiotropium for this variable.

RESULTS

A total of 169 patients were randomized (mean age 65 years); 153 (90.5%) completed. Trough FEV1 after 14 days with indacaterol 150 μg and 300 μg was statistically and clinically superior to placebo, with differences (95% CI) of 170 (120-220) and 150 (100-200) mL respectively (both p < 0.001). For this endpoint, both doses of indacaterol not only met the criterion for non-inferiority compared with tiotropium, but also achieved numerically higher values, with differences versus tiotropium of 40 and 30 mL for indacaterol 150 and 300 μg, respectively. At 5 min post-dose on Day 1, the mean FEV1 for both indacaterol doses was significantly higher than placebo (by 120 and 130 mL for indacaterol 150 and 300 μg, respectively; p < 0.001) and tiotropium (by 80 mL for both doses; p < 0.001). Adverse events were reported by similar proportions of patients: 31.4%, 29.5%, 28.3% and 28.5% for indacaterol 150 μg and 300 μg, tiotropium and placebo treatments, respectively.

CONCLUSIONS

Once-daily indacaterol provided clinically and statistically significant 24-h bronchodilation. Indacaterol was at least as effective as tiotropium, with a faster onset of action (within 5 min) on the first day of dosing. Indacaterol should prove useful in patients with moderate-to-severe COPD, for whom treatment with one or more classes of long-acting bronchodilator is recommended.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00615459, EudraCT number: 2007-004071-19.

Quality of life in patients with chronic obstructive pulmonary disease: which drugs help most?

The treatment of chronic obstructive pulmonary disease (COPD) is receiving increasing attention since the burden of this disease is expected to rise on a global scale in the coming decades. Preventing deterioration of lung function parameters has been the main goal of research in COPD management. In practice, however, the success of drug treatment is not dependent on lung function only, but also relies on the patients' well-being. Therefore, an important role for health-related quality of life (HRQL) is emerging. Until now, several frequently prescribed drugs have been tested in trials using valid and disease-specific HRQL instruments. Evidence of beneficial effects on HRQL is available for the use of short-acting bronchodilators, theophylline and long-acting beta-adrenergic bronchodilators in the treatment of COPD. One source reported beneficial effects of inhaled corticosteroid treatment on HRQL. The value of these and other drugs in the management of COPD will need to be assessed in the coming years.

Treatment of mild chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is an epidemic in many parts of the world. Most patients with COPD demonstrate mild disease. The cornerstone of management of mild disease is smoking cessation, which is the only proven intervention to relieve symptoms, modify its natural history and reduce mortality. For asymptomatic patients, it is the only required therapy. Short-acting bronchodilators can be added on an as needed basis for those with intermittent symptoms and regularly for those with persistent symptoms. Long-acting bronchodilators can be substituted for those who remain symptomatic despite regular use of short-acting bronchodilators. Inhaled corticosteroids do not modify the natural history of COPD and as such cannot be recommended as standalone therapy for mild COPD. However, for patients with refractory and intractable symptoms, they may be used in combination with long-acting beta-2 agonists. Influenza and pneumococcal vaccination and pulmonary rehabilitation are other therapies that may be considered for select patients with mild disease. In this paper, we summarize the current standard of care for patients with mild COPD.

Comparison of the protective effect amongst anticholinergic drugs on methacholine-induced bronchoconstriction in asthma

The protective effect of inhaled anticholinergic drugs in the methacholine-induced bronchospasm is well-known. The objective of this study was to assess if any possible differences may be found among Ipratropium (IB), Oxitropium (OXI) and Tiotropium (TIO) pre-treatments to obtain the protective effect. Forty-four patients with intermittent bronchial asthma and PD(20)FEV(1) < 200 microg were selected (24 M, 20 F; mean age 32 +/- 8.8). On the baseline, they had mean FEV(1)%: 98.8 +/- 8.54 of theoretical and mean PD(15)FEV(1) 111.8 +/- 61.04 microg. After 72 hours, all patients underwent a second methacholine challenge and were given Ipratropium (40 microg by MDI in 14 pts) or Oxitropium (200 microg by MDI in 14 pts) or Tiotropium (18 microg by Handihaler in 16 pts) sixty minutes before the test. Sixty minutes after the bronchodilator inhalation, the FEV(1)% increase was higher (p < 0.05) in OXI (6.7 +/- 4.83%) and TIO groups (6.11 +/- 2.54%) than in the IB group (3.8 +/- 1.96%). In the IB group PD(15)FEV(1) and PD(20)FEV(1) were obtained in all patients, while in the OXI group they were obtained in 12 and 5 pts respectively and in the TIO group in 14 and 5 pts respectively. Normal hyperreactivity was obtained in 2 patients, in both OXI and TIO groups. In OXI and TIO, the PD(15) obtained after drug pre-medication, was similar (respectively 1628 +/- 955.7 and 1595.5 +/- 990 microg), but higher (p < 0.0001) in comparison to the PD(15) measured in the IB group (532.2 +/- 434.8 microg). Also, the dose-response slope (decline percentage of FEV(1)/cumulative methacholine dose) after PD(15) was similar in both OXI and TIO groups but different in the IB group. A significant relationship (p < 0.01) was found between PD(15)FEV(1) (obtained in 40 pts) and the increase in FEV(1)% obtained 60 minutes after bronchodilator inhalations (r = 0.53). In conclusion, with a standard dose, both Oxitropium and Tiotropium seem to have the same protective effect in bronchial asthma but higher than Ipratropium. It's probable that the best dose of Ipratropium should be a higher one than the usual dose taken.

Pharmacological analysis of the interaction of antimuscarinic drugs at M(2) and M(3) muscarinic receptors in vivo using the pithed rat assay

Muscarinic receptor antagonists form the mainstay of the therapeutic options for airway, bladder, and gastrointestinal smooth muscle disorders. Both M(2) and M(3) muscarinic receptors are involved in mediating smooth muscle contractility, although the relative functional contribution of each subtype, especially in the disease state, is unclear. Because the potency and selectivity of compounds for a given receptor in an in vivo setting can be dissimilar to that observed in an in vitro system, we developed an in vivo assay to simultaneously determine the absolute potency and selectivity of muscarinic receptor antagonists at M(2) and M(3) receptors using the pithed rat. Methacholine (MCh)-induced bradycardia and depressor responses were used as surrogate functional endpoints for M(2) and M(3) receptor activation, respectively. The influence of the muscarinic antagonists, tolterodine, oxybutynin, darifenacin, Ro 320-6206, solifenacin, or tiotropium on the MCh-induced responses were studied. The estimated DR(10) values (dose producing a tenfold shift in the MCh curve) of tolterodine, oxybutynin, darifenacin, Ro 320-6206, solifenacin, and tiotropium for the M(2) muscarinic receptor-mediated bradycardia were 0.22, 1.18, approximately 2.6, 0.025, 0.40, and 0.0026 mg/kg, respectively, and 0.14, 0.18, 0.11, 3.0, 0.18, and 0.0017 mg/kg, respectively, for the M(3) muscarinic receptor-mediated depressor response. In a separate set of experiments, a single intravenous dose of tiotropium was administered before a MCh curve at 1, 3, 6, or 9 h to determine if tiotropium exhibited time-dependent selectivity for the M(3) receptor as has been reported from in vitro studies. The results indicate a slight preference of tiotropium for the M(3) receptor at later time points. The pithed rat assay may serve useful for elucidating the functional contribution of M(2) and M(3) receptors to the in vivo pharmacological effects of antagonists in disease animal models.

Tiotropium for the treatment of stable chronic obstructive pulmonary disease: A systematic review with meta-analysis

BACKGROUND

Current guidelines recommend the use of inhaled tiotropium in patients with stable chronic obstructive pulmonary disease (COPD). However, this statement is based on a relatively small number of randomized controlled trials (RCTs) and related systematic reviews. This review was undertaken to incorporate the more recent evidence available about the effectiveness of tiotropium bromide compared with placebo, iptratropium bromide or long-acting beta-agonists (LABAs), for the treatment of stable COPD patients.

DATA SOURCE

Medline, EMBASE, CINAHL, and the Cochrane Controlled Trials Register (to February 2006) were searched to identify all published RCTs. We also searched bibliographies of relevant articles.

RESULTS

Data from 13 RCT (6078 subjects, 80% male) showed that tiotropium reduced COPD-related exacerbations (OR=0.76; 95% CI: 0.68-0.87) and hospital admissions (OR=0.59; 95% CI: 0.47-0.73) compared with placebo. Also, tiotropium showed statistically significant improvement in lung function, including trough, average, and peak FEV(1) and FVC from baseline, compared with placebo and ipratropium. The administration of inhaled tiotropium lead to 30% reduction in COPD-related admissions (OR= 0.67; 95% CI: 0.46-0.98) compared with LABAs. Finally, increases in FEV(1) and FVC from baseline were significantly larger with tiotropium than with LABAs.

CONCLUSIONS

This review clearly supports the beneficial effects of the use of tiotropium in stable moderate-to-severe COPD patients, and increases the evidence in favor of the superiority of tiotropium on LABAs.

Efficacy and safety of tiotropium in COPD patients in primary care--the SPiRiva Usual CarE (SPRUCE) study

BACKGROUND

Clinical trials of tiotropium have principally recruited patients from secondary care with more severe chronic obstructive pulmonary disease (COPD), and typically had included limitation of concomitant medication. In primary care, which is the most common setting for COPD management, many patients may have milder disease, and also may take a broad range of concomitant medication.

METHODS

This randomised, placebo-controlled, parallel-group, 12-week, 44-centre study investigated the efficacy (trough forced expiratory volume in 1 second [FEV1] response) and safety of additional treatment with once-daily tiotropium 18 mug via the HandiHaler in a primary care COPD population (tiotropium: N = 191, FEV1 = 1.25 L [47.91% predicted]; placebo: N = 183, FEV1 = 1.32 L [49.86% predicted]). Secondary endpoints included: trough forced vital capacity (FVC) response, weekly use of rescue short-acting beta-agonist, and exacerbation of COPD (complex of respiratory symptoms/events of >3 days in duration requiring a change in treatment). Treatment effects were determined using non-parametric analysis.

RESULTS

At Week 12, median improvement in trough FEV1 response with tiotropium versus placebo was 0.06 L (p = 0.0102). The improvement was consistent across baseline treatment and COPD severity. Median improvement in FVC at 2, 6 and 12 weeks was 0.12 L (p < 0.001). The percentage of patients with > or =1 exacerbation was reduced (tiotropium 9.5%; placebo 17.9%; p = 0.0147), independent of disease severity. Rescue medication usage was significantly reduced in the tiotropium group compared with placebo. Adverse event profile was consistent with previous studies.

CONCLUSION

Tiotropium provides additional benefits to usual primary care management in a representative COPD population.

TRIAL REGISTRATION

The identifier is: NCT00274079.

Highly sensitive assay for tiotropium, a quaternary ammonium, in human plasma by high-performance liquid chromatography/tandem mass spectrometry

Tiotropium bromide, a long-acting inhaled bronchodilator analogous to ipratropium bromide, is currently undergoing development for the treatment of chronic obstructive pulmonary disease. To evaluate its systemic absorption in humans, we have developed a rapid and sensitive method for its determination in human plasma based on high-performance liquid chromatography with tandem mass spectrometric detection (HPLC/MS/MS). Reversed-phase chromatography of tiotropium and the internal standard clenbuterol was carried out using acetonitrile/10 mM ammonium acetate (1% formic acid) 40:60 as mobile phase in a run time of 3.0 min. The sample preparation involved deproteination with acetonitrile, extraction into dichloromethane and back-extraction into hydrochloric acid. The assay was linear over the concentration range 0.500-50.0 pg/mL with intra- and inter-day precision (as relative standard deviation) both <or=7.34%. The method was successfully applied to a pharmacokinetic study of systemic absorption in healthy male volunteers given a single 18 microg inhaled dose.

Single Dose of Tiotropium Improves the 6-Minute Walk Distance in Chronic Obstructive Pulmonary Disease

The aim of this study was to evaluate the effect of a single dose of tiotropium on the exercise capacity of stable chronic obstructive pulmonary disease (COPD) patients. The study was a randomized, placebo-controlled, double-blind, cross-over study. Forty-four stable COPD patients with moderate to severe airway obstruction were selected according to the GOLD criteria. The regular anticholinergic therapies of the patients were interrupted one week before the test. In the morning hours of the first day, half the group was given one capsule (18 mcg) of tiotropium and the other half was given placebo as inhalation using the HandiHaler device. Before and 120 min after the medication, the 6-min walk test was performed. Oxygen saturation, modified Borg dyspnea ratings, blood pressure, and heart rate were recorded before and after the test. The same procedure was repeated at the same time on the third day but this time the patients were given placebo if they used tiotropium on the first day and vice versa. Before using tiotropium or placebo there was no difference between 6-min walk distances. The 6-min walk distance after the use of tiotropium (429.3 +/- 70.6 m) was significantly longer than that after the use of placebo (414.7 +/- 74.6 m). The changes in Borg dyspnea ratings and arterial oxygen saturation values with tiotropium and placebo use were not significant. We conclude that exercise capacity might be improved by using a single-dose tiotropium inhalation in moderate to severe COPD patients.

Quantifying the association and dissociation rates of unlabelled antagonists at the muscarinic M3 receptor

Slow receptor dissociation kinetics has been implicated in the long clinical duration of action of the muscarinic receptor antagonist tiotropium. However, despite the potential benefits of new drugs with slow dissociation kinetics, the rate parameters of new compounds are seldom measured due to technical difficulties and financial implications associated with radiolabeling multiple ligands. Here we describe the development and optimisation of a medium throughput assay which is capable of measuring the kinetic parameters of novel, unlabelled compounds. Radioligand binding studies were performed with membranes derived from CHO cells recombinantly expressing the human M(3) muscarinic receptor.Initial characterisation of the radioligand [(3)H]-NMS yielded on and off rates of 4.1+/-0.2 x 10(8) M(-1) min(-1) and 0.015+/-0.0005 min(-1), respectively. The specific binding of [(3)H]-NMS was measured over time in the presence and absence of several concentrations of unlabelled competitor compounds. These data were analysed using a competition kinetic model to provide on and off rates for the unlabelled competitor. Comparison of the kinetically derived Kd (k(off)/k(on)) with K(i) values generated at equilibrium showed an excellent correlation (r(2)=0.99), providing good validation of the method. The on and off rates were also used in theoretical computer simulations to successfully predict the effect of incubation time on apparent IC(50) values. This study demonstrates that a medium-throughput competition kinetic binding assay can be used to determine accurate on and off rates of unlabelled compounds, providing the opportunity to optimise for kinetic parameters early in the drug discovery process.

Synthesis and Radiolabelling of Ipratropium and Tiotropium for Use as PET Ligands in the Study of Inhaled Drug Deposition

Ipratropium bromide [(1R,3r,5S,8r,2′RS)-3-(3′-hydroxy-2′-phenylpropionyloxy)-8-isopropyl-8-methyl-8-azabicyclo[3.2.1]octan-8-ium bromide] and tiotropium bromide [(1R,2R,4S,5S,7s)-7-[2′-hydroxy-2′,2′-di(thiophen-2′′-yl)acetoxy]-9,9-dimethyl-9-aza-3-oxatricyclo[3.3.1.02,4]nonan-9-ium bromide] are inhaled drugs used in the treatment of chronic obstructive pulmonary disease (COPD) and asthma. Tertiary amine precursors have been synthesized and radiolabelled with carbon-11 by N-alkylation with [11C]CH3I. The [11C]ipratropium and [11C]tiotropium positron emission tomography (PET) ligands are obtained with high radiochemical purity, in 0.3 and 0.5% non-decay corrected yields based on [11C]CO2 at end-of-synthesis and specific activities of 11 and 18 GBq μmol−1, respectively, calculated at end-of-synthesis. These PET radioligands can be used in the study of inhaled drug deposition.

Drug discovery from medicinal plants

Current research in drug discovery from medicinal plants involves a multifaceted approach combining botanical, phytochemical, biological, and molecular techniques. Medicinal plant drug discovery continues to provide new and important leads against various pharmacological targets including cancer, HIV/AIDS, Alzheimer's, malaria, and pain. Several natural product drugs of plant origin have either recently been introduced to the United States market, including arteether, galantamine, nitisinone, and tiotropium, or are currently involved in late-phase clinical trials. As part of our National Cooperative Drug Discovery Group (NCDDG) research project, numerous compounds from tropical rainforest plant species with potential anticancer activity have been identified. Our group has also isolated several compounds, mainly from edible plant species or plants used as dietary supplements, that may act as chemopreventive agents. Although drug discovery from medicinal plants continues to provide an important source of new drug leads, numerous challenges are encountered including the procurement of plant materials, the selection and implementation of appropriate high-throughput screening bioassays, and the scale-up of active compounds.

Acetylcholine: a novel regulator of airway smooth muscle remodelling?

Increased airway smooth muscle mass is a pathological feature that asthma and chronic obstructive pulmonary disease (COPD) have in common. This increase has gained renewed interest in view of recent developments showing that airway smooth muscle, instead of solely being a contractile partner, is capable of interacting dynamically with its environment, especially under inflammatory conditions. Airway smooth muscle cells are able to proliferate, to migrate, and to secrete chemokines, cytokines, extracellular matrix proteins and growth factors, and most importantly, to adapt to these functions by changing its phenotype from contractile to proliferative/synthetic. Conversely, switching to a (hyper)contractile phenotype may also occur. A vast number of inflammatory stimuli regulate these functions and exert their effects via excitatory G(q) or G(i)-coupled receptors. Since acetylcholine activates muscarinic M(2) and M(3) receptors in the airway smooth muscle cell membrane, which are coupled to G(i) and G(q) proteins, respectively, and since acetylcholine release may be enhanced in airway inflammation, a pathophysiological role of acetylcholine related to the above processes and exceeding contraction could be envisaged. In this review, evidence in favour of this hypothesis, based on recent data that show a role for muscarinic receptors in modulating airway smooth muscle proliferation, contractility and contractile protein expression is discussed. Based on these findings, we postulate that endogenous acetylcholine contributes to airway remodeling in asthma and COPD.

The Effect of Inhaled Tiotropium Bromide on Lung Mucociliary Clearance in Patients With COPD

STUDY OBJECTIVE

To assess the effects of tiotropium on lung mucociliary clearance in COPD.

DESIGN

Randomized, double-blind, placebo-controlled, parallel-group study.

SETTING

Outpatients of an urban-area university teaching hospital.

PATIENTS

Thirty-four patients with COPD aged 40 to 75 years classified equally into two groups.

INTERVENTION

Single (18 microg) daily dose of tiotropium inhalation capsules or of placebo for 21 days.

METHODS

Six-hour tracheobronchial clearance of inhaled 99mTc-labeled polystyrene particles using a 48-h retention measurement to determine the "nontracheobronchial" deposition fraction.

RESULTS

Test radioaerosol penetration into the lungs increased significantly (p < 0.003) as did FEV1 (p < 0.006) in the tiotropium-treated patients, but measured mucociliary clearance was not significantly changed despite the increased pathway length for clearance (mean +/- SE area under the tracheobronchial retention curve changed from 442 +/- 22 to 453 +/- 20%/h). Smaller (nonsignificant) decreases of radioaerosol penetration and FEV1 occurred in the placebo group together with a small (nonsignificant) decrease in the area under the retention curve.

CONCLUSION

Twenty-one days of inhaled tiotropium, 18 microg/d, as a dry powder does not retard mucus clearance from the lungs.